Compositions for microlithography

ABSTRACT

A fluorine-containing polymer prepared from at least a spacer group selected from the group consisting of ethylene, alpha-olefins, 1,1′-disubstituted olefins, vinyl alcohols, vinyl ethers, and 1,3-dienes; and a norbornyl radical containing a functional group containing the structure: —C(R f )(R f′ )Or b  wherein R f  and R f′  are the same or different fluoroalkyl groups of from 1 to about 10 carbon atoms or taken together are (CF 2 ) n  wherein n is an integer ranging from 2 to about 10 and R b  is a hydrogen atom or an acid-base-labile protecting group; r is an integer ranging from 0-4. The fluorine-containing polymer has an absorption coefficient of less than 4.0 mm− 1  at a wavelength of 157 nm. These polymers are useful in photoresist compositions for microlithography. They exhibit high transparency at this short wavelength and also possess other key properties, including good plasma etch resistance and adhesive properties.

FIELD OF THE INVENTION

[0001] The present invention pertains to photoimaging and, inparticular, the use of photoresists (positive-working and/ornegative-working) for imaging in the production of semiconductordevices. The present invention also pertains to novelfluorine-containing polymer compositions having high UV transparency(particularly at short wavelengths, e.g., 157 nm) which are useful inphotoresist compositions and antireflective coatings.

BACKGROUND OF THE INVENTION

[0002] Polymer products are used as components of imaging andphotosensitive systems and particularly in photoimaging systems such asthose described in Introduction to Microlithography, Second Edition byL. F. Thompson, C. G. Willson, and M. J. Bowden, American ChemicalSociety, Washington, D.C., 1994. In such systems, ultraviolet (UV) lightor other electromagnetic radiation impinges on a material containing aphotoactive component to induce a physical or chemical change in thatmaterial. A useful or latent image is thereby produced which can beprocessed into a useful image for semiconductor device fabrication.

[0003] Although the polymer product itself may be photoactive, generallya photosensitive composition contains one or more photoactive componentsin addition to the polymer product. Upon exposure to electromagneticradiation (e.g., UV light), the photoactive component acts to change therheological state, solubility, surface characteristics, refractiveindex, color, electromagnetic characteristics or other such physical orchemical characteristics of the photosensitive composition as describedin the Thompson et al. publication supra.

[0004] For imaging very fine features at the submicron level insemiconductor devices, electromagnetic radiation in the far or extremeultraviolet (UV) is needed. Positive working resists generally areutilized for semiconductor manufacture. Lithography in the UV at 365 nm(I-line) using novolak polymers and diazonaphthoquines as dissolutioninhibitors is a currently established chip technology having aresolution limit of about 0.35-0.30 micron. Lithography in the far UV at248 nm using p-hydroxystyrene polymers is known and has a resolutionlimit of shorter wavelengths, due to a decreasing lower resolution limitwith decreasing wavelength (i.e., a resolution limit of 0.18-0.12 micronfor 193 nm imaging and a resolution limit of about 0.07 micron for 157nm imaging). Photolithography using 193 nm exposure wavelength (obtainedfrom an argon fluorine (ArF) excimer laser) is a leading candidate forfuture microelectronics fabrication using 0.18 and 0.13 μm design rules.Photolithography using 157 nm exposure wavelength (obtained from afluorine excimer laser) is a leading candidate for futuremicrolithography further out on the time horizon (beyond 193 nm)provided suitable materials can be found having sufficient transparencyand other required properties at this very short wavelength. The opacityof traditional near UV and far UV organic photoresists at 193 nm orshorter wavelengths precludes their use in single-layer schemes at theseshort wavelengths.

[0005] Some resist compositions suitable for imaging at 193 nm areknown. For example, photoresist compositions comprisingcycloolefin-maleic anhydride alternating copolymers have been shown tobe useful for imaging of semiconductors at 193 nm (see F. M. Houlihan etal, Macromolecules, 30, pages 6.517-6534(1997); T. Wallow et al. SPIE,Vol. 2724, pages 355-364; and F. M. Houlihan et al., Journal ofPhotopolymer-Science and Technology, 10, No. 3, pages 511-520 (1997)).Several publications are focused on 193 nm resists (i.e., U.Okoroanyanwu et al, SPIE, Vol. 3049, pages 92-103; R. Allen et al.,SPIE, Vol. 2724, pages 334-343; and Semiconductor International,September 1997, pages 74-80). Compositions comprising addition polymersand/or ROMP (ring-opening methathesis polymerization) of functionalizednorbornenes have been disclosed in PCT WO 97/33198. Homopolymers andmaleic anhydride copolymers of norbornadiene and their use in 193 nmlithography have been disclosed (J. Niu and J. Frechet, Angew. Chem.Int. Ed., 37, No. 5, (1998), pages 667-670). Copolymers of flourinatedalcohol-substituted polycyclic ethylenically unsaturated comonomer andsulfur dioxide that are suitable for 193 nm lithography have beenreported (see H. Ito et al., “Synthesis and Evaluation of AlicyclicBackbone Polymers for 193 nm Lithography”, Chapter 16, ACS SymposiumSeries 706 (Micro- and Nanopatterning Polymers) pages 208-223 (1998) andH. Ito et al., Abstract in Polymeric Materials Science and EngineeringDivision, American Chemical Society Meeting, Volume 77, Fall Meeting,Sep. 8-11,1997, held in Las Vegas, Nev.). Because of the presence ofrepeat units derived from sulfur dioxide in this alternating copolymer,it is not suitable for 157 nm lithography due to the excessively highabsorption coefficient of this polymer at 157 nm.

[0006] Photoresists containing fluorinated alcohol functional groupsattached to aromatic moieties have been disclosed (see K. J. Przybillaet al., “Hexafluoroacetone in Resist Chemistry: A Versatile New Conceptfor Materials for Deep UV Lithography”, SPIE Vol. 1672, (1992), pages500-512). While suitable for 248 nm lithography, these resists, becauseof the aromatic functionality contained in them, are unsuitable forlithography at 193 or 157 nm (due to the excessively high absorptioncoefficients of the aromatic resist components at these wavelengths).

[0007] Copolymers of fluoroolefin monomers and cyclic unsaturatedmonomers are disclosed in U.S. Pat. Nos. 5,177,166 and 5,229,473 whichdo not disclose photosensitive compositions. Copolymers of certainfluorinated olefins with certain vinyl esters are known. For example,the copolymer of trifluoroethylene (TFE) with cyclohexanecarboxylate,vinyl ester is disclosed in Japanese Patent Appln. JP 03281664.Copolymers of TFE and vinyl esters, such as vinyl acetate, and use ofthese copolymers in photosensitive compositions for refractive indeximaging (e.g., holography) is disclosed in U.S. Pat. No. 4,963,471 toDuPont.

[0008] Copolymers of norbornene-type monomers containing functionalgroups with ethylene are disclosed in WO 98/56837 and copolymers ofnorbornene-type monomers containing functional groups with vinyl ethers,dienes, and isobutylene, are disclosed in U.S. Pat. No. 5,677,405.Norbornene/ethylene copolymerizations catalyzed by nickel catalysts aredisclosed in U.S. Pat. No. 5,929,181.

[0009] Certain copolymers of fluorinated alcohol comonomers with othercomonomers are disclosed in U.S. Pat. No. 3,444,148 and JP 62186907 A2.These patents are directed to membrane or other non-photosensitive filmsor fibers, and neither has any teaching of fluorinated alcoholcomonomers use in photosensitive layers (e.g., resists), U.S. Pat. No.5,655,627 discloses a process for generating a negative tone resistimage by coating a silicon wafer with a copolymer resist solution ofpentafluoropropyl methacrylate-t-butyl methacrylate in a solvent, andthen exposing at 193 nm and developing with a carbon dioxide criticalfluid.

[0010] A need still exists for resist compositions that satisfy themyriad of requirements for single layer photoresists that includeoptical transparency at 193 nm and/or 157 nm, plasma etch resistance,and solubility in an aqueous base developer.

[0011] In the process of forming patterned microelectronic structures bymeans of lithography, it is common in the art to use one or moreantireflective coatings (ARC) or layers either beneath the photoresistlayer, a BARC, or on top of the photoresist layer, a TARC, (or sometimesreferred to simply as an ARC) or both. Antireflective coating layershave been shown to reduce the deleterious effects of film thicknessvariations and the resulting standing waves caused by the interferenceof light reflecting from various interfaces within the photoresiststructure and the variations in the exposure dose in the photoresistlayer due to loss of the reflected light. The use of theseantireflective coating layers results in improved patterning andresolution characteristics of the photoresist materials because theysuppress reflection related effects.

[0012] A need also exists for antireflective coatings that have opticaltransparency at 193 nm and/or 157 nm.

SUMMARY OF THE INVENTION

[0013] The invention relates to a fluorine-containing polymer comprisingthe reaction product of (A) a spacer group and (B) a repeat unit derivedfrom a monomer containing a norbornyl radical and a functional groupcontaining the structure:

—C(R_(f))(R_(f)′)OR_(b)

[0014] wherein R_(f) and R_(f)′ are the same or different fluoroalkylgroups of from 1 to about 10 carbon atoms or taken together are(CF₂)_(n) wherein n is an integer ranging from 2 to about 10 and R_(b)is a hydrogen atom or an acid- or base-labile protecting group.

[0015] In a first aspect, the invention provides a fluorine-containingpolymer prepared from at least

[0016] (A) a spacer group selected from the group consisting ofethylene, alpha-olefins, 1,1′-disubstituted olefins, vinyl alcohols,vinyl ethers, and 1,3-dienes; and

[0017] (B) a repeat unit derived from a monomer having the followingstructure:

[0018] wherein each of R₁, R₂, R₃, and R₄ independently is hydrogen, ahalogen atom, a hydrocarbon group containing from 1 to 10 carbon atoms,a substituted hydrocarbon group, an alkoxy group, a carboxylic acid, acarboxylic ester or a functional group containing the structure:

—C(R_(f))(R_(f)′)OR_(b)

[0019] wherein R_(f) and R_(f)′ are the same or different fluoroalkylgroups of from 1 to 10 carbon atoms or taken together are (CF₂)_(n)wherein n is 2 to 10; R_(b) is hydrogen or an acid- or base-labileprotecting group; r is 0-4; at least one of the repeat units (B) has astructure whereby at least one of R₁, R₂, R₃, and R₄ contains thestructure C(R_(f))(R_(f)′)OR_(b).

[0020] In a second aspect, the invention provides a photoresistcomposition comprising a fluorine-containing polymer comprising thereaction product of (A) a spacer group and (B) a repeat unit derivedfrom a monomer containing a norbornyl radical and a functional groupcontaining the structure:

—C(R_(f))(R_(f)′)OR_(b)

[0021] wherein R_(f) and R_(f)′ are the same or different fluoroalkylgroups of from 1 to about 10 carbon atoms or taken together are(CF₂)_(n) wherein n is an integer ranging from 2 to about 10 and R_(b)is a hydrogen atom or an acid- or base-labile protecting group, and

[0022] (b) at least one photoactive component

[0023] wherein the fluorine-containing polymer has an absorptioncoefficient of less than 4.0 μm⁻¹ at a wavelength of 157 nm.

[0024] In a third aspect, the invention provides a process for preparinga photoresist image on a substrate comprising, in order:

[0025] (X) imagewise exposing the photoresist layer to form imaged andnon-imaged areas, wherein the photoresist layer is prepared from aphotoresist composition comprising:

[0026] (a) fluorine-containing polymer prepared from at least afluorine-containing polymer comprising the reaction product of (A) aspacer group and (B) a monomer containing a norbornyl radical and afunctional group containing the structure:

—C(R_(f))(R_(f)′)OR_(b)

[0027] wherein R_(f) and R_(f)′ are the same or different fluoroalkylgroups of from 1 to about 10 carbon atoms or taken together are(CF₂)_(n) wherein n is an integer ranging from 2 to about 10 and R_(b)is a hydrogen atom or an acid- or base-labile protecting group; and

[0028] (b) a photoactive component

[0029] wherein the fluorine-containing polymer has an absorptioncoefficient of less than 4.0 μm⁻¹ at a wavelength of 157 nm; and

[0030] (Y) developing the exposed photoresist layer having imaged andnon-imaged areas to form the relief image on the substrate.

[0031] In a fourth aspect, the invention provides for an elementcomprising a support, and at least an antireflection layer; wherein theantireflection layer is prepared from a composition comprising at leastone fluorine-containing polymer prepared from at least afluorine-containing reaction product of (A) a spacer group and (B) amonomer containing a norbornyl radical and a functional group containingthe structure:

—C(R_(f))(R_(f)′)OR_(b)

[0032] wherein R_(f) and R_(f)′ are the same or different fluoroalkylgroups of from 1 to about 10 carbon atoms or taken together are(CF₂)_(n) wherein n is an integer ranging from 2 to about 10 and R_(b)is a hydrogen atom or an acid- or base-labile protecting group.

[0033] The element may further comprise a photoresist layer.

[0034] In a fifth aspect, the invention provides a process for improvedlithographic patterning of a photoresist element having a support, aphotoresist layer and an antireflection layer comprising:

[0035] (Y) imagewise exposing the photoresist element to form imaged andnon-imaged areas, wherein the antireflection layer is prepared from acomposition comprising at least one fluorine-containing polymer preparedfrom at least a fluorine-containing polymer comprising the reactionproduct of (A) a spacer group and (B) a monomer containing a norbornylradical and a functional group containing the structure:

—C(R_(f))(R_(f)′)OR_(b)

[0036] wherein R_(f) and R_(f)′ are the same or different fluoroalkylgroups of from 1 to about 10 carbon atoms or taken together are(CF₂)_(n) wherein n is an integer ranging from 2 to about 10 and R_(b)is a hydrogen atom or an acid- or base-labile protecting group; and

[0037] (Z) developing the exposed photoresist element having imaged andnon-imaged areas to form the relief image on the substrate.

DETAILED DESCRIPTION

[0038] The fluorine-containing polymers of the invention are preparedfrom at least a fluorine-containing polymer comprising the reactionproduct of (A) a spacer group and (B) a monomer containing a norbornylradical and a functional group containing the structure:

—C(R_(f))(R_(f)′)OR_(b)

[0039] wherein R_(f) and R_(f)′ are the same or different fluoroalkylgroups of from 1 to about 10 carbon atoms or taken together are(CF₂)_(n) wherein n is an integer ranging from 2 to about 10 and R_(b)is a hydrogen atom or an acid- or base-labile protecting group.

[0040] Fluorine-Containing Polymer:

[0041] The fluorine-containing polymer is prepared from at least aspacer group (A) and a monomer (B).

[0042] The spacer group is a hydrocarbon compound containing vinylicunsaturation and optionally, containing at least one heteroatom, such asan oxygen atom or a nitrogen atom. The hydrocarbon compound contemplatedas the spacer group contains, typically, 2 to 10, more typically 2 to 6carbon atoms. The hydrocarbon may be straight chain or branched chain.Specific examples of suitable spacer groups are selected from the groupconsisting of ethylene, alpha-olefins, 1,1′-disubstituted olefins, vinylalcohols, vinyl ethers, and 1,3-dienes. Typically, when the spacer groupis an alpha olefin, it is selected from the group consisting ofethylene, propaylene, 1-butene, 1-pentene, 1-hexene and 1-octene.Typically, when the spacer group is a vinyl ether it is selected fromthe group consisting of methyl vinyl ether and ethyl vinyl ether.Typically vinyl alcohols can be obtained by post-polymerizationhydrolysis of a functional group already incorporated into the polymerbackbone, e.g. the acetate group of vinyl acetate. Typically when thespacer group is a 1,3-diene it is butadiene. Typically when the spacergroup is a 1,1′-disubstituted olefin it is isobutylene or isopentene.

[0043] Monomer (B) is an ethylenically unsaturated compound containing anorbornyl radical and a fluoroalcohol functional group.

[0044] These fluoroalkyl groups are designated as R_(f) and R_(f)′,which can be partially fluorinated alkyl groups or fully fluorinatedalkyl groups (i.e., perfluoroalkyl groups).

[0045] Broadly, R_(f) and R_(f)′ are the same or different fluoroalkylgroups of from 1 to about 10 carbon atoms or taken together are(CF₂)_(n) wherein n is an integer ranging from 2 to about 10.

[0046] The terms “taken together” mean that R_(f) and R_(f)′ are notseparate, discrete-fluorinated alkyl groups, but that together they forma ring structure of 3 to about 11 carbon atoms such as is illustratedbelow in case of a 5-membered ring:

[0047] When R_(f) and R_(f)′ are partially fluorinated alkyl groupsthere must be a sufficient degree of fluorination present to impartacidity to the hydroxyl (—OH) of the fluoroalcohol functional group,such that the hydroxyl proton is substantially removed in basic media,such as in aqueous sodium hydroxide solution or tetraalkylammoniumhydroxide solution. Typically, there will be sufficient fluorinesubstitution present in the fluorinated alkyl groups of thefluoroalcohol functional group such that the hydroxyl group will have apKa value as follows: 5<pKa<11.

[0048] Preferably, R_(f) and R_(f)′ are independently perfluoroalkylgroup of 1 to about 5 carbon atoms, and, most preferably, R_(f) andR_(f)′ are both trifluoromethyl (CF₃)

[0049] In a repeat unit derived from a monomer having the structure

[0050] the substituents R₁, R₂, R₃, and R₄ may, independently, be ahydrogen atom, a halogen atom, a hydrocarbon group containing from 1 toabout 10 carbon atoms or a substituted hydrocarbon group. When one ormore substituent R₁, R₂, R₃, and R₄ is a hydrocarbon group the carbonatoms are usually straight chain or branched chain. Typical examplesinclude alkyl groups (methyl (“Me”), ethyl (“Et”), propyl (“Pr”)),carboxylic acid or ester, alkoxy (—OMe, OEt, OPr), halogen (F, Cl, Br).When one or more substituent R₁, R₂, R₃, and R₄ is a substitutedhydrocarbon group, the substituent is typically a heteroatom selectedfrom the group consisting of oxygen atom, typically to form an alkoxygroup, a carboxylic acid group or a carboxylic ester group.

[0051] Copolymers of ethylene and monomers of the formula

[0052] may contain “abnormal” branching (see for example World PatentApplication 96/23010, which is hereby incorporated by reference, for anexplanation of “abnormal” branching). These polymers may typicallycontain more than 5 methyl ended branches per 1000 methylene groups inpolyethylene segments in the polymer, more typically more than 10 methylended branches, and most typically more than 20 methyl ended branches.The branches can impart improved solubility to the ethylene copolymerswhich can be advantageous for preparing photoresists and for otherpurposes. Branching levels may be determined by NMR spectroscopy, seefor instance World Patent Application 96/23010 and other knownreferences for determining branching in polyolefins. By methyl endedbranches are meant the number of methyl groups corrected for methylgroups present as end groups in the polymer. Also not included as methylended branches are groups which are bound to a norbornane ring system asa side group, for example a methyl attached directly to a carbon atomwhich is bound to a ring atom of a norbornane ring system. Thesecorrections are well known in the art. Typically, polymers hereincontain at least one mole percent (based on the total number of allrepeat units in the copolymer) of the norbornene monomer shown above,more typically at least 2 mole percent, and most typically at least 5mole percent. Repeat units derived from one or more othercopolymerizable monomers, such as alpha-olefins and vinyl ethers mayalso optionally be present.

[0053] The free radical polymerization or metal-catalyzed vinyl additionpolymerization processes employed in making the polymerization productsof this invention are accomplished by such polymerization mechanismsknown in the art to afford a polymer having a repeat unit that isderived from the ethylenically unsaturated compound. Specifically, anethylenically unsaturated compound having structure:

[0054] that undergoes free radical polymerization will afford a polymerhaving a repeat unit:

[0055] where P, Q, S, and T independently can be the same or differentand illustratively could be fluorine, hydrogen, chlorine, andtrifluoromethyl.

[0056] If only one ethylenically unsaturated compound undergoespolymerization, the resulting polymer is a homopolymer. If two or moredistinct ethylenically unsaturated compounds undergo polymerization, theresulting polymer is a copolymer.

[0057] Some representative examples of ethylenically unsaturatedcompounds and their corresponding repeat units are given below:

[0058] For metal catalyzed vinyl addition polymerization a usefulcatalyst is a nickel containing complex. Neutral Ni catalysts used inthe patent are described in WO Patent Application 9830609. Otherreferences regarding the salicylaldimine-based neutral nickel catalystsinclude WO Patent Application 9842664. Wang, C.; Friedrich, S.; Younkin,T. R.; Li, R. T.; Grubbs, R. H.; Bansleben, D. A.; Day, M. W.Organometallics 198, 17(15), 314 and Younkin, T.; Connor, E. G.;Henderson, J. I.; Friedrich, S. K.; Grubbs, R. H.; Bansleben, D. A.Science 2000, 287, 460-462. Additional catalysts are disclosed in Ittel,S. D.; Johnson, L. K.; Brookhart, M. Chem. Rev. 2000, 100, 1169-1203 andBoffa, L. S.; Novak, B. M. Chem. Rev. 2000, 100,1479-1493. Moody, L. S.;MacKenzie, P. B.; Killian, C. M.; Lavoie, G. G.; Ponasik, J. A.;Barrett, A. G. M.; Smith, T. W.; Pearson, J. C. WO 0050470 disclosesimprovements variations of largely existing ligands and some new ligandson late metal catalysts, e.g., ligands derived from pyrrole aminesinstead of anilines and also ligands based on anilines with 2,6-orthosubstituents where these ortho substituents are both aryl groups or anyaromatic group. Specific examples would be alpha-diimine-based nickelcatalysts and salicylaldimine-based nickel catalysts derived from thepyrrole amines and ortho-aromatic-substituted anilines. Some of thesederivatives show improved lifetimes/activities/productivities/hydrogenresponse/potential functional group tolerance, etc. Another usefulcatalyst is a functional group tolerant, late metal catalyst usuallybased on Ni(II) or Pd(II). Useful catalysts are disclosed in WO 98/56837and U.S. Pat. No. 5,677,405.

[0059] Methods of preparing copolymers from norbornene-type monomers andcationically polymerizable monomers by employing Group VIII transitionmetal ion sources for said monomers at a temperature in the range from−100° C. to 120° C. are disclosed in U.S. Pat. No. 5,677,405. By“cationically polymerizable monomers” what is meant are monomers such asolefins, isoolefins, branched α-olefins, vinyl ethers, cyclic ethers,and lactones that normally undergo cationic polymerization. Thecopolymers formed from norbornene-type monomers and cationicallypolymerizable monomers have a relatively high norbornene content (˜80mole % in those copolymers that are characterized). Copolymers can beformed using functionalized norbornene comonomers, e.g.5-norbornene-2-methanol and esters derived from 5-norbornene-2-methanol.It is contemplated that the catalysts and methods disclosed in thisapplication will be suitable for the synthesis of the copolymers ofnorbornene fluoroalcohols with 1,3-dienes, 1,1′-disubstituted olefins,and vinyl ethers that are the subject of the present invention. It isfurther contemplated that these copolymers may contain greater thanapproximately 1 mole %, more typically greater than approximately 25mole %, and most typically greater than approximately 50 mole % ofnorbornene fluoroalcohol, with suitable adjustment of the monomer feedratio. Examples of suitable catalysts useful in the preparation of suchcopolymers include norbornadienepalladium dichloride/silverhexafluoroantimonate, methoxynorbornenylpalladium chloride dimer/silverhexafluoroantimonate, and[(η-crotyl)(cycloocta-1,5-diene)nickel]-hexafluorophosphate.

[0060] It is contemplated that in photoresist applications that thecopolymer can include acidic groups, which may or may not be protectedwith acid-labile protecting groups. It is further contemplated thatmonomer units containing these acidic groups constitute greater thanapproximately 1 mole %, more typically greater than approximately 25mole %, and most typically greater than approximately 50 mole % of thepolymer. Examples of acidic groups include carboxylic acids, phenols,and fluroalcohols with pKa values of approximately 9 or less.

[0061] Copolymers of ethylene and protected norbornene fluoroalcoholscan be synthesized using Ziegler-Natta and metallocene catalysts basedon early transition metals. Suitable protecting groups forfluoroalcohols include alpha-alkoxy ethers. Examples of suitablecatalysts may be found in the following references: W. Kaminsky J. Chem.Soc., Dalton Trans. 1988, 1413, and W. Kaminsky Catalysis Today 1994,20, 257.

[0062] Any suitable polymerization conditions may be employed in theprocess of making the polymer. Typically, when metal catalyzed vinyladdition polymerization is used the temperatures are held below about200° C., typically between 0° C. and 160° C. Suitable known solvents maybe used such as trichlorobenzene or p-xylene.

[0063] Each fluorine-containing copolymer according to this inventionhas an absorption coefficient of less than 4.0 μm⁻¹ at a wavelength of157 nm, preferably of less than 3.5 μm⁻¹ at this wavelength, morepreferably, of less than 3.0 μm⁻¹ at this wavelength, and, still morepreferably, of less than 2.5 μm⁻¹ at this wavelength.

[0064] Some illustrative, but nonlimiting, examples of representativecomonomers containing a fluoroalcohol functional group and within thescope of the invention are presented below:

[0065] The fluorine-containing polymer may be photactive, i.e. thephotoactive component may be chemically bonded to thefluorine-containing polymer. This may be accomplished by chemicallybonding the photoactive component to a monomer which then undergoescopolymerization to the monomers (A) and (B) of the present invention,thus eliminating the need for a separate photoactive component.

[0066] The ratio of A and B can be important. Typical ranges for eachare about 30% to about 70%.

[0067] One or more additional monomers (C) may be used in thepreparation of the fluorine-containing polymers of the invention. Ingeneral, it is contemplated that an acrylate monomer may be suitable asa monomer (C) in preparing the polymers of the invention. Typicaladditional monomers include acrylates, olefins containingelectron-withdrawing groups (other than fluorine) directly attached tothe double bond. These polymers, typically terpolymers, may be made byfree-radical polymerization, for example, acrylonitrile, vinyl chloride,vinylidene chloride. Alternately, olefins containing aromatic groupsattached directly to the double bond; e.g. styrene and alpha-methylstyrene (although arguably these are alpha- and 1,1′-disubstitutedolefins) are also useful. Vinyl acetate is also useful as an additionalmonomer.

[0068] These fluorine-containing polymers are useful in preparingphotoresist compositions that comprise the fluorine-containing polymer,at least one photoactive component and optionally a dissolutioninhibitor. The photoactive component may be chemically bonded to thefluorine-containing polymer or it may be a separate component used incombination with the fluorine-containing polymer.

[0069] Photoactive Component (PAC)

[0070] If the fluorine-containing polymer is not photoactive, thecompositions of this invention may contain a photoactive component (PAC)that is not chemically bonded to the fluorine-containing polymer, i.e.the photoactive component is a separate component in the composition.The photoactive component usually is a compound that produces eitheracid or base upon exposure to actinic radiation. If an acid is producedupon exposure to actinic radiation, the PAC is termed a photoacidgenerator (PAG). If a base is produced upon exposure to actinicradiation, the PAC is termed a photobase generator (PBG).

[0071] Suitable photoacid generators for this invention include, but arenot limited to, 1) sulfonium salts (structure I), 2) iodonium salts(structure II), and 3) hydroxamic acid esters, such as structure III.

[0072] In structures I-II, R₅-R₇ are independently substituted orunsubstituted aryl or substituted or unsubstituted C₁-C₂₀ alkylaryl(aralkyl). Representative aryl groups include, but are not limited to,phenyl and naphthyl. Suitable substituents include, but are not limitedto, hydroxyl (—OH) and C₁-C₂₀ alkyloxy (e.g., C₁₀H₂₁O. The anion X— instructures I-II can be, but is not limited to, SbF₆ ⁻(hexafluoroantimonate), CF₃SO₃ ⁻ (trifluoromethylsulfonate=triflate),and C₄F₉SO₃ ⁻ (perfluorobutylsulfonate).

[0073] Dissolution Inhibitor

[0074] Various dissolution inhibitors can be utilized in this invention.Ideally, dissolution inhibitors (DIs) for the far and extreme UV resists(e.g., 193 nm resists) are designed/chosen to satisfy multiple materialsneeds including dissolution inhibition, plasma etch resistance, andadhesion behavior of resist compositions comprising a given DI additive.Some dissolution inhibiting compounds also serve as plasticizers inresist compositions.

[0075] A variety of bile-salt esters (i.e., cholate esters) areparticularly useful as DIs in the compositions of this invention.Bile-salt esters are known to be effective dissolution inhibitors fordeep UV resists, beginning with work by Reichmanis et al. in 1983. (E.Reichmanis et al., “The Effect of Substituents on the Photosensitivityof 2-Nitrobenzyl Ester Deep UV Resists”, J. Electrochem. Soc. 1983, 130,1433-1437.) Bile-salt esters are particularly attractive choices as DIsfor several reasons, including their availability from natural sources,their possessing a high alicyclic carbon content, and particularly fortheir being transparent in the Deep and vacuum UV region of theelectromagnetic spectrum (e.g., typically they are highly transparent at193 nm). Furthermore, the bile-salt esters are also attractive DIchoices since they may be designed to have widely ranging hydrophobic tohydrophilic compatibilities depending upon hydroxyl substitution andfunctionalization.

[0076] Representative bile-acids and bile-acid derivatives that aresuitable as additives and/or dissolution inhibitors for this inventioninclude, but are not limited to, those illustrated below, which are asfollows: cholic acid (IV), deoxycholic acid (V), lithocholic acid (VI),t-butyl deoxycholate (VII), t-butyl lithocholate (VIII), andt-butyl-3-α-acetyl lithocholate (IX). Bile-acid esters, includingcompounds VII-IX, are preferred dissolution inhibitors in thisinvention.

[0077] The amount of dissolution inhibitor can vary depending upon thechoice of polymer. When the polymer lacks sufficient protected acidgroup for suitable image forming a dissolution inhibitor can be used toenhance the image forming properties of the photoresist composition.

[0078] Other Components

[0079] The compositions of this invention can contain optionaladditional components. Examples of additional components which can beadded include, but are not limited to, resolution enhancers, adhesionpromoters, residue reducers, coating aids, plasticizers, solvents andT_(g) (glass transition temperature) modifiers. Crosslinking agents mayalso be present in negative-working resist compositions. Some typicalcrosslinking agents include bis-azides, such as, 4,4′-diazidodiphenylsulfide and 3,3′-diazidodiphenyl sulfone. Typically, a negative workingcomposition containing at least one crosslinking agent also containssuitable functionality (e.g., unsaturated C═C bonds) that can react withthe reactive species (e.g., nitrenes) that are generated upon exposureto UV to produce crosslinked polymers that are not soluble, dispersed,or substantially swollen in developer solution. Examples of suitablesolvents are 2-heptanone, trichlorobenzene, methanol,1,1,2,2-tetrachloroethane, d₂ ethyl ether and p-xylene.

[0080] Process for Forming a Photoresist Image

[0081] The process for preparing a photoresist image on a substratecomprises, in order:

[0082] (X) imagewise exposing the photoresist layer to form imaged andnon-imaged areas, wherein the photoresist layer is prepared from aphotoresist composition comprising:

[0083] (a) fluorine-containing polymer of the invention; and

[0084] (b) at least one photoactive component; and

[0085] (Y) developing the exposed photoresist layer having imaged andnon-imaged areas to form the relief image on the substrate.

[0086] Imagewise Exposure

[0087] The photoresist layer is prepared by applying a photoresistcomposition onto a substrate and drying to remove the solvent. The soformed photoresist layer is sensitive in the ultraviolet region of theelectromagnetic spectrum and especially to those wavelengths less thanor equal to about 365 nm. Imagewise exposure of the resist compositionsof this invention can be done at many different UV wavelengthsincluding, but not limited to, 365 nm, 248 nm, 193 nm, 157 nm, and lowerwavelengths. Imagewise exposure is preferably done with ultravioletlight of 248 nm, 193 nm, 157 nm, or lower wavelengths, preferably it isdone with ultraviolet light of 193 nm, 157 nm, or lower wavelengths, andmost preferably, it is done with ultraviolet light of 157 nm or lowerwavelengths. Imagewise exposure can either be done digitally with alaser or equivalent device or non-digitally with use of a photomask.Digital imaging with a laser is preferred. Suitable laser devices fordigital imaging of the compositions of this invention include, but arenot limited to, an argon-fluorine excimer laser with UV output at 193nm, a krypton-fluorine excimer laser with UV output at 248 nm, and afluorine (F₂) laser with output at 157 nm. Since, as discussed supra,use of UV light of lower wavelength for imagewise exposure correspondsto higher resolution (lower resolution limit), the use of a lowerwavelength (e.g., 193 nm or 157 m or lower) is generally preferred overuse of a higher wavelength (e.g., 248 nm or higher).

[0088] Development

[0089] The fluorine-containing components in the resist compositions ofthis invention must contain sufficient functionality for developmentfollowing imagewise exposure to UV light. Preferably, the functionalityis acid or protected acid such that aqueous development is possibleusing a basic developer such as sodium hydroxide solution, potassiumhydroxide solution, or ammonium hydroxide solution.

[0090] The fluorine-containing polymers in the resist compositions ofthis invention are typically acid-containing materials comprised of atleast one fluoroalcohol-containing monomer of structural unit:

—C(R_(f))(R_(f)′)OH

[0091] wherein R_(f) and R_(f)′ are as previously described. The levelof acidic fluoroalcohol groups is determined for a given composition byoptimizing the amount needed for good development in aqueous alkalinedeveloper.

[0092] When an aqueous processable photoresist is coated or otherwiseapplied to a substrate and imagewise exposed to UV light, development ofthe photoresist composition may require that the binder material shouldcontain sufficient acid groups (e.g., fluoroalcohol groups) and/orprotected acid groups that are at least partially deprotected uponexposure to render the photoresist (or other photoimageable coatingcomposition) processable in aqueous alkaline developer. In case of apositive-working photoresist layer, the photoresist layer will beremoved during development in portions which are exposed to UV radiationbut will be substantially unaffected in unexposed portions duringdevelopment by aqueous alkaline liquids such as wholly aqueous solutionscontaining 0.262 N tetramethylammonium hydroxide (with development at25° C. usually for less than or equal to 120 seconds, typically lessthan 90 seconds and in some instances less than 5 seconds). In case of anegative-working photoresist layer, the photoresist layer will beremoved during development in portions which are unexposed to UVradiation but will be substantially unaffected in exposed portionsduring development using either a critical fluid or an organic solvent.

[0093] A critical fluid, as used herein, is one or more substancesheated to a temperature near or above its critical temperature andcompressed to a pressure near or above its critical pressure. Criticalfluids in this invention are at least at a temperature that is higherthan 15° C. below the critical temperature of the fluid and are at leastat a pressure higher than 5 atmosphers below the critical pressure ofthe fluid. Carbon dioxide may be used for the critical fluid in thepresent invention. Various organic solvents can also be used asdeveloper in this invention. These include, but are not limited to,halogenated solvents and non-halogenated solvents. Halogenated solventsare typical and fluorinated solvents are more typical.

[0094] Substrate

[0095] The substrate employed in this invention can illustratively besilicon, silicon oxide, silicon nitride, or various other materials usedin semiconductive manufacture.

[0096] Other Applications

[0097] Many of the polymers discussed within this application could beused as antireflection layers for semiconductor lithography. Inparticular, since low optical absorption at 157 nm is a prime attributeof the materials being considered here, they should be of particularlyutility at this wavelength.

[0098] Such layers may be applied using many different techniques suchas spin coating, chemical vapor deposition and aerosol deposition. Thedesign of a composition for use as an antireflective layer is well knownto those skilled in the art. The primary optical properties of thematerial being used for the antireflective coating that must beconsidered are the optical absorption and the index of refraction, thefluorine-containing polymer of this invention possesses such properties.

[0099] For this application, the invention provides an elementcomprising a support, and at least an antireflection layer; wherein theantireflection layer is prepared from a composition comprising

[0100] (a) a fluorine-containing polymer of this invention; and

[0101] (b) at least one photoactive component

[0102] The element may further comprise a photoresist layer.

[0103] The invention also provides a process for improved lithographicpatterning of a photoresist element having a support, a photoresistlayer and an antireflection layer comprising:

[0104] (Y) imagewise exposing the photoresist element to form imaged andnon-imaged areas; wherein the antireflection layer is prepared from acomposition comprising a fluorine-containing polymer of this invention;and

[0105] (Z) developing the exposed photoresist element having imaged andnon-imaged areas to form the relief image on the substrate.

[0106] The imaging and development steps are conducted as describedearlier. The antireflection layer may be removed during the developmentof the photoresist having imaged and non-imaged areas or it may beremoved separately using aqueous or solvent development, or byconventional dry etch processes as are know in the art. The photoresistlayer may be any photoresist layer know to one skilled in the art withthe proviso that it has an absorption coefficient of less than 4.0 μm⁻¹at a wavelength of 157 nm. The fluorine-containing polymer has beendescribed in detail earlier in the specification. The antireflectionlayer may be present between the support and the photoresist layer or itmay be present on the surface of the photoresist layer away from thesupport.

[0107] All of the copolymers herein are also useful as molding resins(if thermoplastics) or as elastomers (if elastomeric). Polymerscontaining

[0108] will also often have modified surface properties, for example berelatively hydrophobic because of the fluorine atoms present on thenorbornene-type monomer, or if a hydrophilic group such as hydroxyl ispresent in the first monomer the surface may be relatively hydrophilic.These copolymers are also useful in polymer blends, particularly ascompatibilizers between different types of polymers, for exampleethylene copolymers of this invention may compatibilize blends ofpolyolefins such as polyethylene and more polar polymers such aspoly(meth)acrylates, polyesters, or polyamides.

EXAMPLES

[0109] Abbreviations:

[0110] Me: Methyl

[0111] Et: Ethyl

[0112] Hex: Hexyl

[0113] Am: Amyl

[0114] Bu: Butyl

[0115] Eoc: End-of-chain

[0116] p: Para

[0117] M.W.: Molecular Weight

[0118] Total Me: Total number of methyl groups per 1000 methylene groupsas determined by ¹H or ¹³C NMR analysis

[0119] Cmpd: Compound

[0120] mL: Milliliter

[0121] Press: Pressure

[0122] Temp: Temperature

[0123] Incorp: Incorporation

[0124] BAF═B(3,5-C₆H₃—(CF₃)₂)₄ ⁻

[0125] Nd: Not Determined

[0126] GPC: Gel Permeation Chromatography

[0127] TCB: 1,2,4-Trichlorobenzene

[0128] THF: Tetrahydrofuran

[0129] Rt: Room Temperatures

[0130] Equiv: Equivalent

[0131] MI: Melt Index

[0132] RI: Refractive Index

[0133] UV: Ultraviolet

[0134] M_(w): Weight Average Molecular Weight

[0135] M_(n): Number Average Molecular Weight

[0136] M_(p): Peak Average Molecular Weight

[0137] PDI: Polydispersity; M_(w) divided by M_(n)

[0138] NMR: Nuclear Magnetic Resonance

[0139] E: Ethylene

[0140] g: gram

[0141] h: Hour

[0142] mol: Mole

[0143] mmol: Millimole

[0144] Et₂O: Diethyl Ether

[0145] General Information Regarding Catalyst Syntheses:

[0146] Methods for the synthesis of catalysts A through D, which areused in Examples 1-6, can be found in WO 98/30609.

Procedure for Examples 1, 2 and 3

[0147]

[0148] In a nitrogen-purged drybox, a glass insert with a gas inlet wasloaded with 0.02 mmol of the nickel complex A, B, or C and 40 equiv(0.4095 g) of B(C₆F₅)₃. Trichlorobenzene (9 ml) was added to the glassinsert, which was then cooled to −30° C. in the drybox freezer.Norbornene-HFIP (1.52 g) was dissolved in 1 mL of Et₂O and the resultingsolution was added on top of the frozen trichlorobenzene. The insert wasimmediately cooled again in the −30° C. drybox freezer. The gas inlet ofthe cold insert was covered with electrical tape and the insert wassealed with a greased cap and removed from the drybox atmosphere.Outside of the drybox, the tube was placed in a plastic bag. The bag wassealed, placed in a bucket and surrounded with dry ice. After removingthe electrical tape, the glass insert was transferred to a pressuretube. The pressure tube was sealed, evacuated, placed under ethylene(300 psi) and shaken mechanically for approximately 18 h at roomtemperature (rt). Following the completion of the reaction, methanol(˜20 mL) was added to the glass insert in order to precipitate thepolymer. The copolymer was isolated and dried under vacuum. ¹H NMRspectra were obtained at 113° C. in TCE-d₂(1,1,2,2-tetrachloroethane-d2) using a Bruker 500 MHz spectrometer. ¹³CNMR spectra were obtained unlocked at 140° C. using 310 mg of sample and60 mg CrAcAc (chromium(III) acetylacetonatein a total volume of 3.1 mLTCB (trichlorobenzene) using a Varian Unity 400 NMR spectrometer with a10 mm probe. GPC molecular weights are reported versus polystyrenestandards; conditions: Waters 150° C., trichlorobenzene at 150 ° C.,Shodex columns at −806MS 4G 734/602005, RI detector.

Example 1

[0149] Nickel complex A (0.0102 g) was used and the above generalprocedure was followed. The resulting copolymer of ethylene andnorbornene-HFIP was isolated as 2.77 g of a white powder. ¹H NMR: 1.5mole % norbornene-HFIP incorporated; M_(n)˜3,120; 33.3 totalmethyl-ended branches per 1000 CH₂. ¹³C NMR: 1.4 mole % norbornene-HFIPincorporated. GPC: Bimodal distribution with a small amount of highermolecular weight material present: M_(p)=1,581; M_(w)=19,873;M_(n)=1,118 and M_(p)=64,787; M_(w)=94,613 and M_(n)=55,595.

Example 2

[0150] Nickel complex B (0.0106 g) was used and the above generalprocedure was followed. The resulting copolymer of ethylene andnorbornene-HFIP was isolated as 3.11 g of a white powder. ¹H NMR: 0.8mole % norbornene-HFIP incorporated; M_(n)˜18,040, 42.9totalmethyl-ended branches per 1000 CH₂. ¹³C NMR: 0.92 mole % norbornene-HFIPincorporated.

Example 3

[0151] Nickel complex C (0.0094 g) was used and the above generalprocedure was followed. The resulting copolymer of ethylene andnorbornene-HFIP was isolated as 1.01 g of a white powder. ¹H NMR: 0.3mole % norbornene-HFIP incorporated; M_(n)˜9,240; 29.1 totalmethyl-ended branches per 1000 CH₂. ¹³C NMR: 0.33 mole % norbornene-HFIPincorporated.

Procedure for Examples 4 and 5

[0152] In a nitrogen-purged drybox, a glass insert with a gas inlet was

[0153] loaded with 0.04 mmol of the nickel complex A or D and 20 equiv(0.4095 g) of B(C₆F₅)₃. Trichlorobenzene (9 mL) was added to the glassinsert, which was then cooled to

[0154] −30° C. in the drybox freezer. Norbornene-HFIP (1 mL) wasdissolved in 1 mL of Et₂O and the resulting solution was added on top ofthe frozen trichlorobenzene. The insert was immediately cooled again inthe −30° C. drybox freezer. The gas inlet of the cold insert was coveredwith electrical tape and the insert was sealed with a greased cap andremoved from the drybox atmosphere. Outside of the drybox, the tube wasplaced in a plastic bag. The bag was sealed, placed in a bucket andsurrounded with dry ice. After removing the electrical tape, the glassinsert was transferred to a pressure tube. The pressure tube was sealed,evacuated, placed under ethylene 150 psi) and shaken mechanically forapproximately 18 h at rt. Following the completion of the reaction,methanol (˜20 mL) was added to the glass insert in order to precipitatethe polymer. The copolymer was isolated and dried under vacuum. ¹³C NMRspectra were obtained unlocked at 140° C. using 310 mg of sample and 60mg CrAcAc in a total volume of 3.1 mL TCB using a Varian Unity 400 NMRspectrometer with a 10 mm probe.

[0155] Nickel complex A (0.0211 g) was used and the above generalprocedure was followed. The resulting branched copolymer of ethylene andnorbornene-HFIP was isolated as 2.60 g of a white powder. ¹³C NMR: 0.83mole % norbornene-HFIP incorporated.

Example 5

[0156] Nickel complex D (0.0204 g) was used and the above generalprocedure was followed. The resulting branched copolymer of ethylene andnorbornene-HFIP was isolated as 3.58 g of a white powder. ¹³C NMR: 0.59mole % norbornene-HFIP incorporated.

Example 6

[0157] In a nitrogen-purged drybox, a glass insert with a gas inlet wasloaded with 0.04 mmol of the nickel complex B (0.0205 g) and 20 equiv(0.4095 g) of B(C₆F₅)₃. p-Xylene (8 mL) was added to the glass insert,which was then cooled to −30° C. in the drybox freezer. Norbornene-HFIP(2 mL) was dissolved in 1 mL of Et₂O and the resulting solution wasadded on top of the frozen p-xylene. The insert was immediately cooledagain in the −30° C. drybox freezer. The gas inlet of the cold insertwas covered with electrical tape and the insert was sealed with agreased cap and removed from the drybox atmosphere. Outside of thedrybox, the tube was placed in a plastic bag. The bag was sealed, placedin a bucket and surrounded with dry ice. After removing the electricaltape, the glass insert was transferred to a pressure tube. The pressuretube was sealed, evacuated, placed under ethylene 150 psi) and shakenmechanically for approximately 18 h at room rt. Following the completionof the reaction, methanol (˜20 mL) was added to the glass insert inorder to precipitate the polymer. The copolymer was isolated and driedunder vacuum to yield 1.75 g of a white powder. ¹³C NMR spectra wasobtained unlocked at 140° C. using 310 mg of sample and 60 mg CrAcAc ina total volume of 3.1 mL TCB using a Varian Unity 400 NMR spectrometerwith a 10 mm probe. ¹³C NMR: 2.14 mole % norbornene-HFIP incorporated inthe branched ethylene copolymer.

Examples 7-17

[0158] The following catalysts identified as N-1 to N-4 were made inaccordance with the synthesis described in Examples 22-25.

Procedure for Examples 7-17

[0159] In a nitrogen-purged drybox, a glass insert was loaded with thenickel compound and B(C₆F₅)₃ and, optionally, NaBAF. Next, p-xylene wasadded to the glass insert followed by the addition of NRBF or NBFOH. Theinsert was greased and capped. The glass insert was then loaded in apressure tube inside the drybox. The pressure tube was then sealed,brought outside of the drybox, connected to the pressure reactor, placedunder the desired ethylene pressure and shaken mechanically. After thestated reaction time, the ethylene pressure was released and the glassinsert was removed from the pressure tube. The polymer was separatedinto methanol-soluble and -insoluble fractions by the addition of MeOH(˜20 mL). The insoluble fraction was collected on a frit and rinsed withMeOH. The MeOH was then removed in vacuo to give the MeOH-solublefraction. The polymers were transferred to pre-weighed vials and driedunder vacuum overnight. The polymer yield and characterization were thenobtained.

[0160] NMR Characterization. ¹H NMR spectra were obtained at 113° C. inTCE-d₂ using a Bruker 500 MHz spectrometer. ¹³C NMR spectra wereobtained unlocked at 140° C. using 310 mg of sample and 60 mg CrAcAc ina total volume of 3.1 mL TCB using a Varian Unity 400 NMR spectrometeror a Bruker Avance 500 MHz NMR spectrometer with a 10 mm probe. Totalmethyls per 1000 CH₂ were measured using different NMR resonances in ¹Hand ¹³C NMR spectra. Because of accidental overlaps of peaks anddifferent methods of correcting the calculations, the values-measured by¹H and ¹³C NMR spectroscopy will not be exactly the same, but they willbe close, normally within 10-20% at low levels of comonomerincorporation. In ¹³C NMR spectra, the total methyls per 1000 CH₂ arethe sums of the 1B₁, 1B₂, 1B₃, and 1B₄₊, EOC resonances per 1000 CH₂.The total methyls measured by ¹³C NMR spectroscopy do not include theminor amounts of methyls from the methyl vinyl ends. In ¹H NMR spectra,the total methyls are measured from the integration of the resonancesfrom 0.6 to 1.08 ppm and the CH₂'s are determined from the integral ofthe region from 1.08 to 2.49 ppm. It is assumed that there is 1 methinefor every methyl group, and ⅓ of the methyl integral is subtracted fromthe methylene integral to remove the methine contribution.

[0161] Molecular Weight Characterization. GPC molecular weights arereported versus polystyrene standards. Unless noted otherwise, GPC'swere run with RI detection at a flow rate of 1 mL/min at 135° C. with arun time of 30 min. Two columns were used: AT-806MS and WA/P/N 34200. AWaters RI detector was used and the solvent was TCB with 5 grams of BHTper gallon. In addition to GPC, molecular weight information was attimes determined by ¹H NMR spectroscopy (olefin end group analysis) andby melt index measurements (g/10 min at 190 ° C.). TABLE 1 Ethylene/NRBFCopolymerizations (Total Volume NRBF + p-Xylene = 10 mL; 150 psiEthylene; 205 mg B(C₆F₅)₃; 18 h) NRBF Cmpd Temp NRBF Yield^(a) IncorpTotal Ex (mmol) ° C. mL g mol % M.W. Me 7 N-1 60 4 2.64 308 M_(p) =16,574; 24.0 (0.04) (¹³C) M_(w) = 17,428; (¹³C) M_(n) = 4,796; PDI =3.63 8 N-1 60 2 4.12 1.57 M_(p) = 12,408; 16.3 (0.04) (¹³C) M_(w) =14,206; (¹³C) M_(n) = 5,798; PDI = 2.45 9 N-1 90 4 3.72 2.34 M_(p) =7,045; 20.0 (0.04) (¹³C) M_(w) = 7,850; (¹³C) M_(n) = 2,452; PDI = 3.2010 N-1 90 2 9.19 2.15 M_(p) = 7,599; 19.2 (0.04) (¹³C) M_(w) = 8,085;(¹³C) M_(n) = 3,313; PDI = 2.44 11 N-1 120 4 14.69 4.80 32.0 (0.04)(¹³C) (¹³C) 12 N-1 120 2 17.96 0.79 M_(p) = 4,673; 15.8 (0.04) (¹³C)M_(w) = 5,037; (¹³C) M_(n) = 1,937; PDI = 2.60 # polymers as viscousoils and also their methanol-solubility is consistent with them beingcopolymers of NRBF and ethylene. Yield and appearance of MeOH-solublefractions:

[0162] TABLE 2 Ethylene/NBFOH Copolymerizations (Total Volume NBFOH + p-Xylene = 10 mL; 50 psi Ethylene; 90° C.; 205 mg B(C₆F₅)₃; 177 mg NaBAF;18 h) NBFOH Cmpd NBFOH Yield^(a) Incorp Total Ex (mmol) mL g mol % M.W.Me 13 N-2 2 0.431 0.56 M_(n)(¹H) = 4,370 12.1 (0.04) (¹³C) (¹³C) 14 N-32 0.301 0.05 M_(n)(¹H) = 2,942 12.7 (0.04) (¹H) 15 N-4 2 0.119 Trace(0.04) (¹H) 16 N-1 2 1.07 075 M_(n)(¹H) = 2,560 14.4 (0.04) (¹³C) (¹³C)17 N-1 4 1.46 0.85 130.4  (0.04) (¹³C) (¹³C) # oils/amorphous solids andalso their methanol-solubility is consistent with them being copolymersof NBFOH and ethylene. Yield and appearance of MeOH-soluble fractions:

[0163] TABLE 3 ¹³C NMR Branching Analysis for Some Ethylene Copolymers(MeOH- Insoluble Fractions) of NRBF and NBFOH Total Hex+ Am+ Bu+ & Ex MeMe Et Pr Bu & eoc & eoc eoc 1 23.3 13.1 3.2 0.6 0.9 5.3 5.6 6.4 2 39.331.3 2.8 1.3 0.8 1.4 2.3 3.9 4 50.5 37.2 5.0 1.5 1.4 4.1 5.2 6.8 5 50.518.5 6.3 0.8 2.6 16.8 21.2 24.9 6 30.7 12.3 4.0 0.7 1.2 9.1 11.6 13.8 724.0 17.2 2.1 0.2 0.6 2.5 4.4 4.4 8 16.3 10.2 2.2 0.3 0.5 2.7 4.3 3.6 920.0 10.8 1.7 0.4 0.8 4.5 6.6 7.1 10 19.2 9.8 1.1 0.1 0.6 5.3 7.1 8.2 1132.0 20.6 0.0 0.5 0.8 7.0 10.1 11.0 12 15.8 3.7 0.0 0.4 0.9 8.6 8.8 11.713 12.1 6.8 0.3 0.1 1.8 4.5 4.4 4.9 16 14.4 5.6 0.8 0.1 1.2 5.9 5.3 7.817 130.4 110.4 7.3 1.2 35.6 9.2 13.1 11.5

[0164] TABLE 4 GPC Data for Ethylene/NRBF Copolymers of Examples 5 and 6Ex M_(w) M_(n) M_(p) PDI 5 4,892 427 364 11.47 6 111,129 915 495 121.41

Example 18

[0165] Example 6 was repeated with the exception that the procedure andmethods used for Examples 7-17 were followed. That is, themethanol-soluble polymer fraction was isolated as well as themethanol-insoluble polymer fraction. NRBF owas used as the comonomer.

[0166] The yield of the methanol-insoluble fraction was 0.19 g. Theyield and characterization of the methanol-soluble fraction was 0.75 g:29.61 mole percent NRBF incorporation; 44.7 Me/1000 CH₂; Mn: No olefins.

Example 19

[0167] The following solution was prepared and magnetically stirredovernight. Component Wt. (gm) The methanol-soluble fraction of the 0.192copolymer in Example 9 2-Heptanone 2.134 t-Butyl Lithocholate 0.0506.82% (wt) solution of 0.125 triphenylsulfonium nonaflate dissolved in2-heptanone which had been filtered through a 0.45μ PTFE syringe filter.

[0168] Spin coating was done using a Brewer Science Inc. Model-100CBcombination spin coater/hotplate on a 4 in. diameter Type “P”, <100>orientation, silicon wafer Development was performed on a Litho TechJapan Co. Resist Development Analyzer (Model-790).

[0169] The wafer was prepared by depositing 6 mL of hexamethyldisilazane(HMDS) primer and spinning at 5000 rpm for 10 seconds. Then about 1 mLof the above solution, after filtering through a 0.45 μm PTFE syringefilter, was deposited and spun at 2500 rpm for 60 seconds and baked at120° C. for 60 seconds.

[0170] 248 nm imaging was accomplished by exposing the coated wafer tolight obtained by passing broadband UV light from an ORIEL Model-82421Solar Simulator (1000 watt) through a 248 nm interference filter whichpasses about 30% of the energy at 248 nm. Exposure time was 30 seconds,providing an unattenuated dose of 20.5 mJ/cm². By using a mask with 18positions of varying neutral optical density, a wide variety of exposuredoses were generated. After exposure the exposed wafer was baked at 100°C. for 60 seconds.

[0171] The wafer was developed in aqueous tetramethylammonium hydroxide(TMAH) solution (OHKA NMD-W, 2.38% TMAH solution) for approximately 2seconds. This test generated a positive image with a clearing dose of2.7 mJ/cm².

Example 20

[0172] The following solution was prepared and magnetically stirredovernight. Component Wt. (gm) The methanol-soluble fraction of the 0.142copolymer in Example 9 2-Heptanone 2.134 t-Butyl Lithocholate 0.1006.82% (wt) solution of 0.125 triphenylsulfonium nonaflate dissolved in2-heptanone which had been filtered through a 0.45μ PTFE syringe filter.

[0173] The wafer coating, imaging and developing procedure as describedin Example 19 was followed except the development time was for 60seconds. This test generated a positive image with a clearing dose of8.3 mJ/cm².

Example 21

[0174] The following solution was prepared and magnetically stirredovernight. Component Wt. (gm) The methanol-soluble fraction of the 0.142copolymer in Example 18 2-Heptanone 2.134 t-Butyl Lithocholate 0.1006.82% (wt) solution of 0.125 triphenylsulfonium nonaflate dissolved in2-heptanone which had been filtered through a 0.45μ PTFE syringe filter.

[0175] The wafer coating procedure as described in Example 19 wasfollowed. A photoresist film of suitable quality was formed on thesubstrate. However, the quantity of polymer was insufficient to permit adetermination of the proper settings for image formation.

General Methods and Information for Ligand Precursor and CatalystSyntheses for Examples 22-25

[0176] All operations related to the catalyst syntheses were performedin a nitrogen-purged drybox. Anhydrous, de-oxygenated solvents were usedin all cases and were either purchased as such from Aldrich or werepurified by standard methods. The solvents were then stored over 4 Åmolecular sieves in the drybox. NaBAF was purchased from BoulderScientific and Ni[II] allyl halide precursors were prepared according tostandard literature methods. (Tert-butyl)₂PCH₂Li was synthesized byreacting (tert-butyl)₂PCH₃ (purchased from Strem) with equimolartertbutyl lithium (purchased from Aldrich) in heptane at 109° C. for afew hours. The product was collected on a frit and washed with pentane.

[0177] NMR spectra were recorded using a Bruker 500 MHz spectrometer ora Bruker 300 MHz spectrometer.

Example 22

[0178] Synthesis of N-1. A 500 mL round-bottom flask was charged with536 mg (5.40 mmol) of t-butylisocyanate dissolved in ca. 30 mL of THF.

[0179] Then (t-Bu)₂PCH₂Li (898 mg, 5.40 mmol) dissolved in ca. 30 mL ofTHF was added. The reaction mixture was stirred for one hour. Next, asolution of [Ni(C₃H₅)(μ-Cl)]₂ (730 mg, 2.70 mmol) in THF (ca. 30 mL) wasadded, and the reaction mixture was stirred for an additional one hourand the solvent was then removed in vacuo. The residue was washed withhexane and dried in vacuo to yield 1.80 g (83%) of a purple powder. ¹H10 NMR (CD₂Cl₂, 23° C., 300 MHz): δ6.0−4.0 (broad signals), 4.0−2.0(broad signals), 1.0−0.0 (broad signals, t-Bu);³¹P³¹P NMR (CD₂Cl₂, 23°C., 300 MHz): δ46.7 (s).

Example 23

[0180] Synthesis of N-2. 2,4-Dimethoxyphenylisocyanate (1.078 g) and(t-Bu)₂PCH₂Li (1.00 g) were weighed in separate vials. Approximately 5mL of THF was added to each vial and the vials were capped and cooled to−30° C. in the drybox freezer. The cold (t-Bu)₂PCH₂Li solution was addedto the cold 2,4-dimethoxyphenylisocyanate solution and the reactionmixture was stirred overnight. The solution was filtered and the THF wasremoved in vacuo. The product was washed with toluene, leaving behindthe lithium salt of the ligand as 0.67 g of a cream powder: ³¹P NMR(C₆D₆) δ6.69 and 0.00. This lithium salt of the ligand (0.43 g),[(H₂CC(CO₂Me)CH₂)Ni(μ-Br)]₂ (0.27 g) and NaBAF (1.00 g) were then placedin a round bottom flask and dissolved in about 20 mL of Et₂O. Thereaction mixture was stirred overnight. The product was filtered througha frit with dry diatomaceous earth. The solvent was removed and theproduct was dried in vacuo to give N-2 together with 1 equiv of(Li/Na)BAF as 1.46 g of an orange-brown powder: ³¹P NMR(CD₂Cl₂) 60.1(major); 62.1 (minor).

Example 24

[0181] Synthesis of N-3. Phenyl isocyanate (0.22 g) and 0.30 g of(t-Bu)₂PCH₂Li were weighed in separate vials. Approximately 3 mL of THFwas added to each vial. The phenyl isocyanate solution was added to thesolution of (t-Bu)₂PCH₂Li and the reaction mixture was stirredovernight. The next day, [(H₂CC(CO₂Me)CH₂)Ni(μ-Br)]₂ (0.43 g) wasweighed in a separate vial and dissolved in several mL of THF. Theresulting solution was added to the reaction mixture, which was thenstirred overnight again.

[0182] The solvent was removed in vacuo. The product was dissolved intoluene and filtered. The solvent was removed and the product was driedin vacuo to give 0.53 g of a red powder: ³¹P NMR (C₆D₆) δ54.1 (major).

Example 25

[0183] Synthesis of N-4. 2,6-Dimethylphenyl isocyanate (0.27 g) and 0.30g of (t-Bu)₂PCH₂Li were weighed in separate vials. Approximately 3 mL ofTHF was added to each vial. The 2,6-dimethylphenyl isocyanate solutionwas added to the solution of (t-Bu)₂PCH₂Li and the reaction mixture wasstirred overnight. The next day, [(H₂CC(CO₂Me)CH₂)Ni(μ-Br)]₂ (0.43 g)was weighed in a separate vial and dissolved in several mL of THF. Theresulting solution was added to the reaction mixture, which was thenstirred overnight again. The solvent was removed in vacuo. The productwas dissolved in Et₂O and filtered through a frit with diatomaceousearth. The solvent was removed and the product was dried in vacuo toyield 0.75 g of a red-brown powder: ³¹P NMR (C₆D₆) δ51.7 (major).

What is claimed is:
 1. A fluorine-containing polymer prepared from atleast (A) a spacer group selected from the group consisting of ethylene,alpha-olefins, 1,1′-disubstituted olefins, vinyl alcohols, vinyl ethers,and 1,3-dienes; and (B) a repeat unit derived from a monomer having thefollowing structure:

wherein each of R₁, R₂, R₃, and R₄ independently is hydrogen, a halogenatom, a hydrocarbon group containing from 1 to 10 carbon atoms, asubstituted hydrocarbon group, an alkoxy group, a carboxylic acid, acarboxylic ester or a functional group containing the structure:—C(R_(f))(R_(f)′)OR_(b) wherein R_(f) and R_(f)′ are the same ordifferent fluoroalkyl groups of from 1 to 10 carbon atoms or takentogether are (CF₂)_(n) wherein n is 2 to 10; R_(b) is hydrogen or anacid- or base-labile protecting group; r is 0-4; at least one of therepeat units (B) has a structure whereby at least one of R₁, R₂, R₃, andR₄ contains the structure C(R_(f))(R_(f)′)OR_(b).
 2. Thefluorine-containing polymer of claim 1 wherein the absorptioncoefficient is less than 4 μm⁻¹ at a wavelength of 157 nm.
 3. Thefluorine-containing polymer of claim 1 wherein the absorptioncoefficient is less than 3.5 μm⁻¹ at a wavelength of 157 nm.
 4. Thefluorine-containing polymer of claim 1 wherein R_(f) and R_(f)′ areindependently a perfluoroalkyl group of 1 to 5 carbon atoms.
 5. Thefluorine-containing polymer of claim 4 wherein R_(f) and R_(f)′ aretrifluoromethyl.
 6. The fluorine-containing polymer of claim 1 whereinthe spacer group is selected from the group consisting of ethylene,propylene, isobutylene, ethyl vinyl ether and butadiene.
 7. Aphotoresist composition comprising (a) a fluorine-containing polymerprepared from at least (A) a spacer group selected from the groupconsisting of ethylene, alpha-olefin, 1,1′-disubstituted olefin, vinylalcohol, vinyl ether, and 1,3-diene; and (B) a repeat unit derived froma monomer having the following structure:

wherein each of R₁, R₂, R₃, and R₄ independently is hydrogen, a halogenatom, a hydrocarbon group containing from 1 to 10 carbon atoms, asubstituted hydrocarbon group, an alkoxy group, a carboxylic acid, acarboxylic ester or a functional group containing the structure:—C(R_(f))(R_(f)′)OR_(b) wherein R_(f) and R_(f)′ are the same ordifferent fluoroalkyl groups of from 1 to carbon atoms or taken togetherare (CF₂)_(n) wherein n is 2 to 10; R_(b) is hydrogen or an acid- orbase-labile protecting group; r is 0-4; at least one of the repeat units(B) has a structure whereby at least one of R₁, R₂, R₃, and R₄ containsthe structure C(R_(f))(R_(f)′)OR_(b), and (b) at least one photoactivecomponent wherein the fluorine-containing polymer has an absorptioncoefficient of less than 4.0 μm⁻¹ at a wavelength of 157 nm.
 8. Thephotoresist composition of claim 7 wherein the fluorine-containingpolymer has an absorption coefficient of less than 3.5 μm⁻¹ at awavelength of 157 nm.
 9. The photoresist composition of claim 7 whereinthe the fluorine-containing polymer has an absorption coefficient ofless than 3.0 μm⁻¹ at a wavelength of 157 nm.
 10. The photoresistcomposition of claim 7 wherein R_(f) and R_(f)′ are independently aperfluoroalkyl group of 1 to 5 carbon atoms.
 11. The photoresistcomposition of claim 10 wherein R_(f) and R_(f)′ are trifluoromethyl.12. The photoresist composition of claim 7 wherein the spacer group isselected from the group consisting of ethylene, propylene, isobutylene,ethyl vinyl ether and butadiene.
 13. The photoresist composition ofclaim 7 wherein the fluoroalcohol functional group containing monomer isselected from the group consisting of


14. The photoresist composition of claim 7 further comprising a solvent.15. The photoresist composition of claim 14 wherein the solvent isselected from the group consisting of trichlorobenzene, methanol,1,1,2,2tetrachloroethane-d₂, ethyl ether, p-xylene and 2-heptanone. 16.The photoresist composition of claim 7 wherein the photoactive componentis chemically bonded to the fluorine-containing polymer.
 17. Thephotoresist composition of claim 7 wherein the photeactive component isnot chemically bonded to the fluorine-containing polymer.
 18. Thephotoresist composition of claim 7 further comprising a dissolutioninhibitor.
 19. A process for preparing a photoresist image on asubstrate comprising, in order: (X) imagewise exposing the photoresistlayer to form imaged and non-imaged areas wherein the photoresist layeris prepared from a photoresist composition comprising: (a) afluorine-containing polymer prepared from at least (A) a spacer groupselected from the group consisting of ethylene, alpha-olefin,1,1′-disubstituted olefin, vinyl alcohol, vinyl ether, and 1,3-diene;and (B) a repeat unit derived from a monomer having the followingstructure:

wherein each of R₁, R₂, R₃, and R₄ independently is hydrogen, a halogenatom, a hydrocarbon group containing from 1 to 10 carbon atoms, asubstituted hydrocarbon group, an alkoxy group, a carboxylic acid, acarboxylic ester or a functional group containing the structure:—C(R_(f))(R_(f)′)OR_(b) wherein R_(f) and R_(f)′ are the same ordifferent fluoroalkyl groups of from 1 to 10 carbon atoms or takentogether are (CF₂)_(n) wherein n is 2 to 10; R_(b) is hydrogen or anacid- or base-labile protecting group; r is 0-4; at least one of therepeat units (B) has a structure whereby at least one of R₁, R₂, R₃, andR₄ contains the structure C(R_(f))(R_(f)′)OR_(b); and (b) at least onephotoactive component wherein the fluorine-containing polymer has anabsorption coefficient of less than 4.0 μm⁻¹ at a wavelength of 157 nm;and (Y) developing the exposed photoresist layer having imaged andnon-imaged areas to form the relief image on the substrate.
 20. Theprocess of claim 19 wherein the fluorine-containing polymer has anabsorption coefficient of less than 3.5 μm⁻¹ at a wavelength of 157 nm.21. The process of claim 19 wherein the the fluorine-containing polymerhas an absorption coefficient of less than 3.0 μm⁻¹ at a wavelength of157 nm.
 22. The process of claim 19 wherein the photoactive component ischemically bonded to the fluorine-containing polymer.
 23. The process ofclaim 19 wherein the photoactive component is not chemically bonded tothe fluorine-containing polymer.
 24. The process of claim 19 wherein thedeveloping step is less than about 5 seconds.
 25. The process of claim19 further comprising a solvent.
 26. The process of claim 25 wherein thesolvent is selected from the group consisting of trichlorobenzene,methanol, 1,1,2,2-tetrachloroethane-d₂, ethyl ether, p-xylene and2-heptanone.
 27. A copolymer consisting of repeat units derived fromethylene and at least one monomer of the structure:

wherein each of R₁, R₂, R₃, and R₄ independently is hydrogen, a halogenatom, a hydrocarbon group containing from 1 to 10 carbon atoms, asubstituted hydrocarbon group, an alkoxy group, a carboxylic acid, acarboxylic ester or a functional group containing the structure:—C(R_(f))(R_(f)′)OR_(b) wherein R_(f) and R_(f)′ are the same ordifferent fluoroalkyl groups of from 1 to 10 carbon atoms or takentogether are (CF₂)_(n) wherein n is 2 to 10; R_(b) is hydrogen or anacid- or base-labile protecting group; r is 0-4; at least one of therepeat units (B) has a structure whereby at least one of R₁, R₂, R₃, andR₄ contains the structure C(R_(f))(R_(f)′)OR_(b); and wherin thecopolymer comprises at least 5 methyl ended branches per 1000 methylenegroups.
 28. The copolymer of claim 27 comprising at least 10 methylended branches per 1000 methylene groups.
 29. The copolymer of claim 27wherein the monomer is selected from the group consisting of:


30. The copolymer of claim 27 wherein at least 1 mole percent of repeatunits derived from the at least one monomer are present in saidcopolymer.
 31. The copolymer of claim 27 wherein repeat units derivedfrom at least one additional monomer are also present in said copolymer.32. A process for making the fluorine-containing polymer of claim 1comprising contacting a spacer group comprising an alpha-olefin and therepeat unit and a catalytically effective amount of a transition metalcatalyst under polymerization conditions to form the fluorine-containingpolymer.
 33. The process of claim 31 in which the alpha-olefin isethylene, the transition metal catalyst comprises nickel and thepolymerization conditions comprise a temperature below 200° C.